The invention relates to a drive unit for a door.
A drive unit of this type is know from the German Patent Application DE 102 27 110 A1. This drive unit functions as a garage door drive. As a component of the drive unit, a guide rail with therein disposed guide element in the form of a tensioned chain is mounted on the garage ceiling. A carriage can be moved back and forth along the guide rail with the aid of an electric motor, wherein the electric motor engages via a toothed gear in the chain. The carriage itself is connected is hinged with the aid of a rod to a door panel. The electric motor is controlled with the aid of an external control unit. Depending on the drive, the electric motor moves the carriage back and forth in a predetermined direction along the guide rails, thereby lowering or lifting the door panel and opening or closing the garage.
Inserted into the guide rail is an insert element, which contains a fixture for tensioning the chain that functions as a guide element. A connecting cable furthermore ends at the insert element and leads to the external control unit, which is preferably attached to one wall of the garage and can be connected there to an outlet for the power supply. Power to the electric motor inside the carriage is supplied via the chain and the guide rail. One lead of the connecting cable is embodied hook-shaped in this case and is conductively connected to the guide element tensioning fixture that is connected to the chain. A different lead of the connecting cable is conducted to a contact that ends on the side of the insert element and fits flush against the guide rail.
The electrical contact, embodied in this way, for supplying power to the electric motor requires an undesirably high expenditure for the assembly and installation.